Belt printer with conductive elements on non-conductive belt

ABSTRACT

An arrangement for printing from a resilient continuous belt carrying miniature chargeable elements capable of being selectively loaded by a recording head in accordance with received information signals. The selective loading of the chargeable elements creates on the belt invisible charge patterns which attract powder applied thereto, resulting in the formation of visible images to be subsequently transferred to a permanent recording medium a line at a time.

United States Patent Staller et a1.

[54] BELT PRINTER WITH CONDUCTIVE ELEMENTS ON NON-CONDUCTIVE BELT [72] Inventors: Karel Jan Staller, Rutherford, N..l.;

Hertwig Lange, Riverside, Conn.

[73] Assignee: International Telephone Telegraph Corporation, Nutley, NJ.

[22] Filed: Nov. 7, 1969 [21] Appl. No.: 874,744

[52] US. Cl. ..197/1 R, l01/D1G. l3, 101/1 [51] Int. Cl. ..B4lj 3/18 [58] Field of Search ..lOl/DlG. l3, 1; 197/1 [56] References Cited UNITED STATES PATENTS 2/ 1964 Supemowicz ..101/D1G. 13 6/1966 Carlson ..101/D1G. 13 5/1961 Hickersom. ...10l/DlG. 13 4/1969 Markgraf ..-10l/DlG. 13

[ 511 Aug. 15, 1972 r 3,400,213 9/1968 l-lell ..lOl/DIG. 13 3,023,070 2/ 1962 Benn ..lOl/DIG. 13 3,321,768 5/1967 Byrd ..101/D1G. 13 3,422,753 1/1969 Strassner et al.....l0l/DIG. 13 3,257,222 6/ 1966 Carlson ..IOI/DIG. 13 3,495,268 2/1970 Hurst ..101/D1G. 13

Primary Examiner-Edgar S. Burr AttorneyC. Cornell Remsen, .lr., Walter J. Baum, Paul W. Hemminger, Percy P. Lantzy, Philip M. Bolton, Isidore Togut and Charles L. Johnson, Jr.

[57] ABSTRACT An arrangement for printing from a resilient continuous belt carrying miniature chargeable elements capable of being selectively loaded by a recording head in accordance with received information signals. The selective loading of the chargeable elements creates on the belt invisible charge patterns which attract powder applied thereto, resulting in the formation of visible images to be subsequently transferred to a permanent recording medium a line at a time.

9 Claims, 12 Drawing Figures PATENTEDAUB 15 m2 SHEET 1 BF 3 INVENTORS KAREL J. STALLfR HRTWI mugs AGENT fl n qnmu PATENTEDAUGISISTZ 3.684075 sum 3 OF 3 KAREL J. STALLfR AGENT INVENTORS BELT PRINTER WITH CONDUCTIVE ELEMENTS ON NON-CONDUCTIVE BELT BACKGROUND OF THE INVENTION The invention relates to apparatus for printing information contained in signals applied thereto, and more particularly to a printer arrangement operating in the range of 300 characters per second utilizing a continuous printing belt carrying chargeable elements.

In the medium-to-fast-running printer art a substantial portion of the line printers require the use of expensive metallic drums carrying rows of alphabets. Among the fastest known arrangements are those which utilize a line of tiny electromagnets which create magnetized dots on a drum or. band forming characters from these dots, a line at a time as built up in mosaic form. The printing head which carries the electromagnets in such arrangements, as well as the electronic controls involved are both complicated and expensive, and require as a matter of necessity storage device arrangements for each incoming line of text.

SUMMARY OF THE INVENTION It is therefore an object of this invention to provide a highly reliable, low-cost printer which eliminates the 'need for expensive storage devices and specialized drums, and which is capable of operational speeds in the range of 300 characters per second.

According to the broader aspects of the invention there is provided a printer arrangement comprising a continuous moving belt of resilient material which carries a multiplicity of small chargeable elements such as capacitors or deposits of magnetizable or electrostatically chargeable material, means in synchronism with the movement of said belt for selectively charging said elements in accordance with received information signals, forming thereby on the belt invisible charge patterns in serial form representative of individual characters of said information, powder applicator means for forming on said belt visible powder images of said charge patterns, and means in synchronism with said belt for transferring said visible images to a moving permanent recording medium, such as a continuous roll of paper, a line at a time, wherein the visible images suffer a reversal in the transfer to the permanent recording medium. One advantage to the invention is that a line of text may be read immediately after it has been transferred to the permanent recording medium, especially if the belt is made from a transparent plastic.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other features according to the invention will be better understood from the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 shows in a perspective view the arrangement according to the invention for printing, via a continuous print belt, information contained in signals applied thereto;

FIGS. 2a-2e illustrate portions of various constructions for the printing belt according to the invention;

FIGS. 2b'2e are end views of FIGS. 2b-2e respectively FIG. 3 illustrates in a perspective view a recording head arrangement according to the invention; and

FIG. 4 shows in a perspective view a modified arrangement of part of the printer shown in the drawing The arrangement according to the invention as shown in FIG. 1 includes a belt 1 of resilient material such as plastic, woven plastic fabric, or rubber which carries a multiplicity of chargeable elements 3 (FIG. 2), and which is stretched between pulleys 2 to be driven thereby in a closed loop. Belt arrangements other than the preferred closed loop are not to be excluded in this invention, such as a rewindable take-up reel arrangement. In fixed arrangement with one of the pulleys 2 is an electromagnetic clutch 17 or other suitable means for driving the belt loop in the direction indicated by the arrow A either continuously or under the control of received signals. As indicated by the arrow, the movement of the belt 1 is horizontal and to the right, with the recording surface In thereof vertically oriented.

A recording head 7 is positioned adjacent to the belt 1 for forming character charge patterns thereon by electrostatically influencing certain ones of the chargeable elements 3 in accordance with the received infor-.

the belt 1 as indicated by the arrow B. The arrangement is such as to permit the paper 19 to pass between the belt 1 and the plate 16 so as to be parallel to the belts recording surface 1a and the transfer face 16a of the plate 16. The paper 19 in turn is stretched and guided by rollers in the direction indicated past a heater 14, illustrated in FIG. 1 as a coil infiguration, which permanently fixes the transferred images to the paper. The paper may preferably be preheated to permit a reduction in the power requirement of heater 14 to perform its function.

FIGS. 2a-2e illustrate various constructions of the belt 1 according to the invention. In FIG. 2a is shown a thin foil of resilient material 4, for example plastic, to which is attached to both surfaces a copper or nickel sheet 4a of perhaps 0.001 inches in thickness. Utilization of photoresist coating and photographic methods serve to etch away portions of the metallic sheets 4a in a predetermined design, leaving only small islands 3a (FIG. 2b) on both sides of the foil 4 of resilient material. As can be readily seen in the end view of FIG. 2b, the multiplicity of small metallic islands 30 on one side are substantially opposite those on the other side, thus forming tiny capacitors the size of which are in the area of 0.010 inches in center-to-center measurements between adjacent islands. The capacitor formation process is such as to provide chargeable elements 3 in a uniform distribution of rows and columns, i.e. coordinate matrix form, although other patterns may be utilized. Substantially the same result may be achieved as shown in FIG. 20 via the process of vacuum coating through a mask 5, with capacitors being formed from the island deposits of metal 3b on the resilient foil 4. 7

Another belt arrangement is illustrated in FIG. 2d, in which a sheet of resilient material 4, for example rubber, is perforated with a multiplicity of holes 30, also distributed in coordinate matrix form and with center-to-center measurements therebetween equivalent to that shown in FIG. 2b. The perforations are filled with conductive rubber (for the cases in which the resilient material used is rubber), which is a mixture of rubber and metallic powder, capable of retaining electrostatic charge. As is the case with all belt constructions disclosed herein, a belt configuration having conductive bodies 30 would permit the deposition of electrostatic charges from either side. An alternative of the belt construction of FIG. 2d would be to fill the perforations 3c with a magnetizable ferrite powder composition. In such a situation, however, the recording head utilized for the other above-defined belt arrangements would be replaced by a row of tiny electromagnets which are energizable in a manner similar to that for the electrostatic cases.

There is illustrated in FIG. 2e yet another belt construction in which the resilient material 4 consists of woven plastic fabric. In this case the cavities 3d in the woven fabric are filled with an elastic conductive material with similar properties to the hereinbeforementioned conductive rubber. Insulation is provided mutually by the fibers of the fabric; thus is formed by this configuration a printing belt also capable of retaining selective electrostatic charge and which is readily accessible from either belt surface.

Referring now to FIG. 3, there is shown a preferred embodiment of the recording head 7 for imparting to the multiplicity of elements 3 on the printing belt 1 coordinated electrostatic charge patterns representative of the received information signals. A center shaft 20, is provided preferably of non-conductive material, on which are placed parallel pointed conductive sheets 8 separated by insulating inserts 9 of substantially equivalent shape. The dimensions of the active (pointed) end of a sheet 8 is such as to correspond substantially to the surface area of a belt element 3. The pointed ends form a row of element-charging points arranged to be substantially perpendicular to the direction of movement of the belt. Each sheet 8 is constructed with a tab portion to which is connected an energizing wire. This energizing wire is in turn connected to a transformer arrangement, indicated generally at 10, of which only one is shown for purposes of clarity' In the preferred arrangement, the number of conductive sheets 8 is equal to the number of chargeable elements 3, for example in number, in any row thereof, as running across the width of the belt 1, though such a correlation between sheets 8 and elements 3 is not deemed a necessary requirement. In accordance with this preferred arrangement, the insulating components 9 should be no greater in thickness than the separation distance between elements 3. The arrow 11 is illustrative of the fact that the recording head 7 via shaft is capable of oscillation, in synchronism with the received signals, between an element-charging position in close proximity to the belt 1 and an inactive position of predetermined remoteness from the belt 1. The oscillation as described provides for the smooth charging of the belt elements 3.

Referring again to FIG. 1, operation of the printing arrangement commences upon the receipt of character input signals by conventional means not shown. In response thereto, the electromagnetic clutch 17, is released to drive the belt 1 in the direction of the arrow A. The information characters received are preliminarily fed to a conversion circuit (also not shown) to be transformed for presentation to the recording head 7. In the alternative the conversion circuit could be eliminated by transmitting the information character signals in such a form as to enable the direct application thereof to the head 7.

With the belt 1 moving past the head 7 at a rate dependent upon the frequency of the incoming signals, the chargeable elements 3 are selectively loaded in accordance with the received signals to provide a serial row of characters corresponding to a line of text. Each character charge pattern covers substantially the full width of the belt 1, and is recorded in the inverse to compensate for the reversal suffered in the transfer of the character to the perrnanant recording medium 19. In generating the character charge patterns, the selective loading of the elements 3 is accomplished by presenting to the corresponding sheets 8 (FIG. 3) of the head 7 high voltage pulses via their respective transformers 10 and associated energizing wires.

As shown in FIG. 3, the letter T generally indicated at 21 has been recorded on a portion of the belt 1 by the head 7. This could have been accomplished for instance by applying five consecutive high voltage pulses to sheet 8a via its transformer 10 and energizing wire, while similarly pulsing the other sheets 8 simultaneously with the third activation of the sheet 8a, the procedure being synchronized throughout with the movement of the belt 1. In like manner invisible electrostatic charge patterns of characters received previous and subsequent to'the T are formed to generate the line of text. For an operating rate of 300 carriers per second, the speed of the belt would be about 30 inches per second. The frequency of loading of the chargeable elements 3 in such a case would be approximately 3 ,000 per second.

The movement of the belt 1 in the direction of the arrow A carries the invisible charge patterns past the powder applicator 12 which applies to the outer surface la of the belt 1 finely divided powder particles. The particles adhere electrostatically to the charge patterns, transforming them into visible two-dimensional images. The powder color may be chosen to offer adequate contrast with the permanant recording medium 19 to which the images are subsequently transferred. The applicator may be of any suitable known type which permits the application of powder in a finely distributed manner.

The powder images pass relative to the cleaning device 13, which may take the form of any suitable known device, where substantially all powder particles not sufficiently attracted by the electrostatic charge patterns are removed. In this manner there is assured a uniform distribution of powder and cleaning of the spaces between the letters.

Further movement of the belt 1 carries the powder images around to the. return side of the closed loop where the transfer plate 16 is encountered. When an entire line of text is in the transfer position, i.e. opposite the paper 19, a high voltage pulse is received by the plate 16, in synchronism with the belt's movement, which generates on the transfer face 16a of the plate 16 an electrostatic field the strength of which is greater than the electrostatic hold on the particles maintained in the belt. There results a transfer simultaneously of each character image of the line of text to the stretched paper 19. Since the line of text wasrecorded on the belt 1 in the inverse the reversal suffered in the transfer to the paper 19 results in a true image reproduction.

Similarly, successive lines of text are recorded on the belt 1 and then transferred to the paper 19 via periodic high voltage charges supplied by means not shown. The interval between the periodic high voltage pulses is such as to permit the belt '1 to move into the transfer position the next full line of text. If the high voltage pulses introduced to the plate 16 are sufficiently short in duration, there would be possible a continuous motion of the paper 19 throughout, rather than require a starti stop motion in synchronism with the movement of the belt 1 andhence the rate of incoming signals.

As the lines are recorded, the vertical movement of the permanent recording medium 19 carries'the ex posed text to the fixing station which consists primarily of a heater coil or element 14, where the powder particles are permanently attached to the paper 19.' The particles, in the interim between transfer to the paper 19 and the permanent attachment thereto by heater 14, are held to the paper basically by electrostatic charges retained in the paper as a result of the transfer process. Also, there is a certain amount of adhesion between the particles and the paper which is enhanced somewhat by the powder particles being embedded in the paper to a small degree as a result of the rapid acceleration characteristics of the transfer process. As previously mentioned, the arrangement according to the invention provides for the display of a 'line of text immediately after transfer.

FIG. 4 illustrates a modification of the arrangement of FIG. 1, in that the recording surface as well as the movement of the belt 1 is horizontal. In addition, and as a result of the belt orientation, the paper 19 is also permitted a horizontal movement as indicated by the arrow C. Of particular note is the fact that the horizontal arrangement of the paper 19 in FIG. 4

avoids the loss sustained in the arrangement of FIG. 1

of some transferred powder particles due to gravity.

The recording head 6 in this embodiment is placed on the inside of the closed loop, i.e. operates on the belt via its inner surface lb while powder applicator 12 and image transfer plate 16 operate on the recorded charge patterns from the outer surface of the belt 1, i.e. surface la. This arrangement is possible in view of the belt construction as hereinbefore disclosed in reference to FIGS. 2b2e, wherein the chargeable elements 3a-3d extend throughout the thickness of the belt 1 either physically or operatively so as to be accessible from either belt surface. As illustrated in FIG. 4 the invisible charges applied to the elements 3 extending through to the opposite belt surface. It is to be noted that since the loading of the elements 3 takes place from the inner surface lb of the belt 1, it is required that such record ing be in trueimage form in view of the reversal suf' fered between belt surfaces. Also, since the powder applicator 12 in this embodiment is applying the powder particles vertically upwards, there: most likely would be no need for the cleaning device 13 of FIG. 1, as its function would be largely replaced by gravity. Arrows 18 are illustrative of the fact that a line of text can be read immediately following the transfer thereof tothe paper 19. i

What is claimedis:

l. A belt printing arrangement comprising:

a. a movable belt of resilient non-conductive base material with first and second sides and having a multiplicity of conductive non-con-tiguous chargeable elements arranged to be repeated on both said sides to form minute capacitors distributed in a regular array;

. means positioned for selectively charging said elements in accordance with received information signals, forming thereby invisible charge patterns representative of said information;

c. powder applicator means for forming on said belt visible images of said charge patterns; and

d. means for transferring said visible images to a movable permanent recording medium.

2. A belt printing arrangement comprising:

a. a movable belt of resilient non-conductive base material having a multiplicity of conductive noncontiguous chargeable elements, said chargeable elements being formed of minute deposits of resilient material impregnated with metallic powder filling perforations in said belt which are arranged in a regular array;

. means positioned for selectively charging said elements in accordance with received information signals, forming thereby invisible charge patterns representative of said information;

c. 'powder applicator means for forming on said belt visible images of said charge patternsyand d. means for transferring said visible images to a movable permanent recording medium.

3. A belt printing arrangement comprising:

a. a movable belt of resilient non-conductive base material having a multiplicity of conductive noncontiguous chargeable elements, said chargeable elementsbeing formed of deposits of magnetizable ferrite powder filling perforations in said 'belt which are arranged in a regular array;

. means positioned for selectively charging said elements in accordance with received information signals, forming thereby invisible charge patterns representative of said information;

c. powder applicator means forforming on said belt visible images of said charge patterns; and

d. means for transferring said visible images to a movable permanent recording medium.

4. The arrangement according to claim 3 wherein said means for selectively charging said elements include a recording head comprised of a row of electromagnets selectively energizable in synchronism with the movement of said belt.

5. A belt printing arrangement comprising:

a. a movable belt constructed as a woven fabric of resilient material, and having a multiplicity of conductive non-contiguous chargeable elements provided therein, said chargeable elements consisting of deposits of elastic conductive material filling the cavities of said woven fabric, and being insulated mutually by the fibers of the woven fabric;

b. means positioned for selectively charging said elements in accordance with received information signals, forming thereby invisible charge patterns representative of said information;

c. powder applicator means for forming on said belt visible images of said charge patterns; and

(1. means for transferring said visible images to a movable permanent recording medium.

6. In a belt printing arrangement, the combination comprising: i

a. a movable belt of resilient non-conductive base material with firs and second sides and having a multiplicity of conductive non-contiguous chargeable elements arranged on both sides of said belt in a regular array and chargeable from either side of said belt;

b. means positioned for selectively charging said elements in accordance with received information signals, forming thereby invisible charge patterns representative of the received information, said means for selectively charging including a recording head consisting of a plurality of parallel pointed conductive sheets separated by insulating inserts of substantially corresponding shape, each sheet being coupled to an energization circuit, the pointed ends of said sheets collectively forming a row of element-charging points arranged to be substantially perpendicular to the direction of movement of said belt; c. powder applicator means for forming on said belt visible images of said charge patterns; and

means for transferring said visible images to a movable permanent recording medium.

7. The arrangement according to claim 6 wherein said means for transferring said visible images include a conductive plate positioned to remove electrostatically the powder images on said belt and transfer same to said permanent recording medium upon the receipt of periodic high voltage pulses.

8. The arrangement according to claim 7 further including a heater, positioned from said plate in the direction of movement of said medium, for attaching thereto the transferred powder images representative of received information signals.

9. The arrangement according to claim 7 wherein said conductive plate is, with respect to said belt, positioned adjacent to the opposite surface of said permanent recording medium and is parallel to said medium and to said belt, and wherein said periodic pulses received by said plate have a rate of generation in which said pulses are spaced apart in time to define, between a consecutive pair thereof, a time interval during which said belt receives a full line of text which, in the course of receipt thereof, is moved into the transfer position, with the movement of said recording medium corresponding to said time intervals so as to effect interline spacing. 

1. A belt printing arrangement comprising: a. a movable belt of resilient non-conductive base material with first and second sides and having a multiplicity of conductive non-con-tiguous chargeable elements arranged to be repeated on both said sides to form minute capacitors distributed in a regular array; b. means positioned for selectively charging said elements in accordance with received information signals, forming thereby invisible charge patterns representative of said information; c. powder applicator means for forming on said belt visible images of said charge patterns; and d. means for transferring said visible images to a movable permanent recording medium.
 2. A belt printing arrangement comprising: a. a movable belt of resilient non-conductive base materIal having a multiplicity of conductive non-contiguous chargeable elements, said chargeable elements being formed of minute deposits of resilient material impregnated with metallic powder filling perforations in said belt which are arranged in a regular array; b. means positioned for selectively charging said elements in accordance with received information signals, forming thereby invisible charge patterns representative of said information; c. powder applicator means for forming on said belt visible images of said charge patterns; and d. means for transferring said visible images to a movable permanent recording medium.
 3. A belt printing arrangement comprising: a. a movable belt of resilient non-conductive base material having a multiplicity of conductive non-contiguous chargeable elements, said chargeable elements being formed of deposits of magnetizable ferrite powder filling perforations in said belt which are arranged in a regular array; b. means positioned for selectively charging said elements in accordance with received information signals, forming thereby invisible charge patterns representative of said information; c. powder applicator means for forming on said belt visible images of said charge patterns; and d. means for transferring said visible images to a movable permanent recording medium.
 4. The arrangement according to claim 3 wherein said means for selectively charging said elements include a recording head comprised of a row of electromagnets selectively energizable in synchronism with the movement of said belt.
 5. A belt printing arrangement comprising: a. a movable belt constructed as a woven fabric of resilient material, and having a multiplicity of conductive non-contiguous chargeable elements provided therein, said chargeable elements consisting of deposits of elastic conductive material filling the cavities of said woven fabric, and being insulated mutually by the fibers of the woven fabric; b. means positioned for selectively charging said elements in accordance with received information signals, forming thereby invisible charge patterns representative of said information; c. powder applicator means for forming on said belt visible images of said charge patterns; and d. means for transferring said visible images to a movable permanent recording medium.
 6. In a belt printing arrangement, the combination comprising: a. a movable belt of resilient non-conductive base material with firs and second sides and having a multiplicity of conductive non-contiguous chargeable elements arranged on both sides of said belt in a regular array and chargeable from either side of said belt; b. means positioned for selectively charging said elements in accordance with received information signals, forming thereby invisible charge patterns representative of the received information, said means for selectively charging including a recording head consisting of a plurality of parallel pointed conductive sheets separated by insulating inserts of substantially corresponding shape, each sheet being coupled to an energization circuit, the pointed ends of said sheets collectively forming a row of element-charging points arranged to be substantially perpendicular to the direction of movement of said belt; c. powder applicator means for forming on said belt visible images of said charge patterns; and d. means for transferring said visible images to a movable permanent recording medium.
 7. The arrangement according to claim 6 wherein said means for transferring said visible images include a conductive plate positioned to remove electrostatically the powder images on said belt and transfer same to said permanent recording medium upon the receipt of periodic high voltage pulses.
 8. The arrangement according to claim 7 further including a heater, positioned from said plate in the direction of movement of said medium, for attaching thereto the transferred powder images representative of received informatiOn signals.
 9. The arrangement according to claim 7 wherein said conductive plate is, with respect to said belt, positioned adjacent to the opposite surface of said permanent recording medium and is parallel to said medium and to said belt, and wherein said periodic pulses received by said plate have a rate of generation in which said pulses are spaced apart in time to define, between a consecutive pair thereof, a time interval during which said belt receives a full line of text which, in the course of receipt thereof, is moved into the transfer position, with the movement of said recording medium corresponding to said time intervals so as to effect interline spacing. 